Securing head for safety ski bindings

ABSTRACT

There is disclosed a securing head for a safety ski binding that is capable for use as either a toe binding member or a heel binding member which includes two lever shaped jaws engageable with a ski boot and each turnable about an axis that is approximately vertical in relation to the ski and said jaws being urged to boot engaging position by at least one spring. Both jaws being the long lever arms of double arm levers, the short arms of which are acted on by a spring through a stroke reducer or motion or displacement limiting member which functions to shorten the axial movement of the spring in relation to the displacement of or stroke of the short lever arms when a force is exerted tending to move the jaws to release position.

United States Patent [72] Inventor Hans Martin 6 Volkmarstrasse, Zurich,Switzerland [21] Appl. No. 860,614

[22] Filed Sept. 24, 1969 [45] Patented Mar. 30, 1971 [32] Priority Oct.4, 1968 [33] Switzerland [54] SECURING HEAD FOR SAFETY SKI BINDINGS3,232,631 2/1966 Witschard 280/l1.35I-IA FOREIGN PATENTS 1,269,5535/1968 Germany 280/ll.35HA

Primary Examiner-Kenneth H. Betts Assistant Examiner-Robert R. SongAttorney-Werner W. Kleeman ABSTRACT: There is disclosed a securing headfor a safety ski binding that is capable for use as either a toe bindingmember or a heel binding member which includes two lever shaped jawsengageable with a ski boot and each tumable about an axis that isapproximately vertical in relation to the ski and said jaws being urgedto boot engaging position by at least one spring. Both jaws being thelong lever arms of double arm levers, the short arms of which are actedon by a spring through a stroke reducer or motion or displacementlimiting member which functions to shorten the axial movement of thespring in relation to the displacement of or stroke of the short leverarms when a force is exerted tending to move the jaws to releaseposition.

PATENTED man I9?! Fig. 5

INVENTOR HAW: A/AiPT/n ATTORNEY J.

SECURING HEAD IFOR SAFETY SIG BINDINGS BACKGROUND OF THE INVENTION Thepresent invention relates broadly to the art of ski bindings.

More particularly, this invention relates to a securing head for asafety ski binding of the type which can be for cooperation with the toeand/or heel portions of a ski boot and which binding comprises twolever-shaped, spring biased jaws, engageable with a ski boot, and eachtumable about an axis which is approximately vertical in relation to theski.

Safety ski bindings are known in the prior art. They are all basedessentially on the principle that the binding releases when a certainforce is exceeded.

Ina first group of known ski bindings, a spring loaded catch, latch,ball, pawl or the like is cooperable with a notch or socket. If theforce acting upon the binding exceeds a certain value, then the catch,latch, ball, pawl or the like disengages from the notch or socket andthe boot is released. The length of the path of travel which the notchor socket makes until release occurs is very short, so that even verybrief impacts can cause release of the binding under conditions in whicha release of the binding would not be necessary. Attempts have been madeto obviate this drawback by a correspondingly increased springtensioning, but this reduces the safety factor of the binding.

In a second group of known ski bindings, springs act directly upon theholding jaws or clamps of the bindings. In normal position, these jawsare under a certain spring load or tension which increases linearly asthe jaw moves out laterally, until the ski boot is released after thejaw has reached a certain position. Due to the limited space availablefor mounting bindings on the ski, one uses short, thick springs havingrelatively steep spring characteristics. As a result, the spring load ortension in normal position differs substantially from the spring load ortension during release of the binding. Thus, one has the choice ofincreasing the spring load for normal position which makes the releaseforce very large and thus endangers the skier, or one adjusts thesprings to accommodate a lower release force in which event the load ortension is too low in normal position. Thus, the jaws would yield inresponse to forces which are of less magnitude then would be requiredfor the safety of the skier. This also is undesirable.

SUMMARY OF THE INVENTION Accordingly, it is an object of this inventionto provide securing head arrangement for safety ski bindings that avoidsthe drawbacks and disadvantages of the known safety ski bindings.

In order to have a ski binding meet all requirements, it must be soconstructed and arranged that the jaw means can be adjusted withsufficient spring load or tension in the normal position as would ensurefirm seating of the binding, and at the same time the force required toeffect release must not be essentially above the binding force or valuein the normal position. Moreover, it is also necessary that a certainlength of path he traveled between normal position and release positionso that brief impacts, although greater than the spring pressure innormal position, thus causing the jaw means to yield, will not causerelease of the binding so that the jaws can spring back into normalposition.

Thus, it is an object of this invention to provide an arrangement thatmeets the above requirements and includes jaw means in the form of twodouble arm levers each having a short lever arm and a long lever arm,with spring means acting directly on the short lever arms through theintermediary of a stroke reducer or motion or displacement limitingmember for reducing the motion effective at the spring in contrast tothe motion of the short lever arm. As a result one obtains a flatterload characteristic of the jaw.

According to a feature of the invention, the stroke reducer or motion ordisplacement limiting member is slidable relative to the end surface ofone of the short lever arms and performs a lateral movement as it isshifted or retracted. The stroke reducer is suitably a triangular shapedsliding member two of whose sides cooperate with the end surfaces of theshort lever arms and whose third side or base serves as a supportsurface for a pressure spring. By virtue of the lateral yield of thesliding member, the displacement tensioning the spring is less than thedisplacement or movement of the short lever arm when it is moving in therelease direction.

According to a preferred embodiment the double arm lever is constructedas an angle lever whose short lever arm contacts in normal position ahead piece in which an adjusting screw is supported for continuousadjustment of the tension of the pressure spring. The use of an anglelever results in a particu larly compact construction of the securinghead.

As a further feature, the adjusting screw passes through the slidingmember and the pressure spring which is biased between one washerscrewed upon the adjusting screw and another washer that bears againstthe base of the sliding member.

In a modified form of the invention one of the two short lever arms hasa' marginal protrusion whereby the short lever arms have different orunequal effective lengths. The short lever arms are constructed in thisfashion so that the forces tending to push the jaws outwardly to arelease position is unequal as regards the two jaws in that a largerforce is required to release one jaw than is required to release theother. Preferably, the short lever arm having the longer effectivelength is provided on the jaw engaging the ski boot on the inside of thefoot, since a greater force is exerted when the foot turns inwardlyvAccording to a further feature of the invention, the sliding member isprovided with a lever arm engaging nose having the shape ofa segment ofacircle.

Additionally the arms of the double arm lever suitably form anapproximate right angle.

BRIEF DESCRIPTION OF THE DRAWINGS Further and more specific objects andadvantages of the present invention will become more readily apparentfrom the following description when taken in connection with theaccompanying drawings in which:

FIG. I is a side elevational view of the securing head of thisinvention;

FIG. 2 is a view partly in top plan and partly in horizontal section andillustrating the component parts of the invention;

FIG. 3 is a fragmentary view illustrating the operation of the slidablestroke reducer or motion or displacement limiting member of theinvention;

FIG. 4 is a fragmentary top plan view illustrating a slidable member ofthe invention having a lever arm engaging nose shaped as a segment of acircle; and

FIG. 5 is a similar view illustrating an arrangement of the securinghead of the invention in which one of the short lever arms of the jawsis provided with a marginal protrusion so that the short lever arms havedifferent effective lengths.

DETAILED DES CRIPTION OF THE PREFERRED EMBODIMENTS In the drawings,reference numeral I denotes the base or securing plate of the securinghead, the former being secured directly to ski la, for example by meansof screws 2. To said securing plate 1 there is articulated a head piece6 as shown in FIG. I, by means of a hinge-joint 3 comprising a pin 4 anda hinge-joint eyelet 5. Headpiece 6 can be slightly biased, if required,by means of a flat spring, now shown. If it is not required that thesecuring head be able to pivot or tilt, then headpiece 6 is mountedrigidly upon the ski.

Headpiece 6 is equipped with a bore 7 in which is accommodated anadjusting screw 8. This screw 8 passes through a sliding member 9, andan axially movable spring washer l0 and has externally threaded portionII at its end upon which is screwed a second spring Washer 12. Betweenboth spring washers 10, 12, there is provided a pressure spring I3 whosetension can be adjusted continuously by turning screw 8. In thearrangement as shown, pressure spring 13 supports itself on springwasher l2 and exerts force via the longitudinally or axially movablespring washer upon sliding member 9.

The sliding member 9 has the shape of a triangular member whose sides14, FIG. 3, contact inclined or slanted surfaces 15 of the short leverarms I6 of angle levers I7. Both long lever arms 18 of the angle levers17 form at their free end jaws for holding the ski boot I9, denoted by adotted line. Further, the free ends of the short lever arms are'forkedso as to fit around the adjusting screw 8.

The headpiece 6 includes a projecting cover part 20 which serves as aprotection for the interior parts.

The securing head operates as follows:

The sliding member 9 which is under a spring force pushes the shortlever arms I6 to bear against the inside wall of headpiece 6 and thushold jaws 18 in normal inward position. If now a lateral force acts uponski boot l9, acting from top to bottom in the drawings, for example,then the lower jaw is pushed outwardly provided that the lateral forceis greater than the counterforce being applied by virtue of the springtension, FIG. 3. In moving outwards, the lower jaw rotates or pivotsaround a pin or bolt 22 which is secured in headpiece 6 and extendsnearly vertical along axis 22a, FIG. I. As the short lever arm 16 turns,sliding member 9 is retracted, but during this phase, the lattersimultaneously performs a lateral displacement. If one now looks at thetip of the short arm 16 of jaw I8 which is swung out, and the tip ofsliding member 9, one can see that the tip of sliding member 9 has beendisplaced axially of screw 8 a distance less than that of the tip ofshort lever arm 16 although in nonnal position, FIG. 1, both tips are onthe same level. Thus, a reduction in stroke or displacement has beenachieved by sliding member 9 so that the spring 13 has been compressedsubstantially less than would otherwise correspond to the stroke ordisplacement of the tip of short lever arm I6. As a result, thecounterforce acting upon the jaw increases correspondingly less thanwould otherwise be the case if it were to correspond to the springcharacteristic of spring 11. Thus, one achieves the initial mentionedobjective, namely that the counterforce acting upon the jaw independency upon the path of travel which it takes as it swings at outincreases only very slightly although the jaw has a relatively long pathof travel at its disposal.

It is now possible to adjust the counterforce of or spring pressureacting on the jaw in normal position so strongly that the jaw remainspermanently firm during normal skiing. As soon as a short or briefimpact occurs which is greater than the force acting on the jaw, the jawyields without, however, releasing the binding and springs back intonormal position after termination of such an impact. Only when a forceis exerted for a longer period of time which is greater than thecounterforce of the jaw, will the ski boot be turned out completely orreleased from the securing head, without the counterforce of or forceacting on the jaw being substantially higher at the moment of releasethan in normal position.

Thus, sliding member 9 acts together with the sliding surfaces of theshort lever arms 16 as stroke reducer or motion limiting member in thatit yields laterally in addition to its axial movement. For this reason,the opening for the adjusting screw 8 in sliding member 9 must have theshape of a slot 23. FIG. 3 will illustrate how the sliding member 9 isdisplaced laterally relative to spring washer 10.

In FIG. 4, the sliding member, only diagrammatically illustrates, amember 24 having its nose in the shape of a segment of a circle.However, its function is the same as that of sliding member 9 in FIG. 3.With the choice of different shapes of sliding members, the stroke ormotion characteristic of said sliding member and thus the characteristicof the spring force in dependency upon the travel of rotation of the jawcan be varied or influenced.

Up to now, one has not paid attention to the fact that when the footturns inwardly, it can take up and also exert a greater force.Accordingly from a physiological viewpoint, the securing head should beconstructed to accommodate differential forces arising during therelease of the ski binding. This can be achieved in the instant securinghead by constructing the short lever arms of different lengths, in that,for example, in connection with the jaw on the inside of the foot, theshort lever arm is made somewhat longer than the short lever arm of thejaw on the outside of the foot. Thus, FIG. 5 illustrates how thisproblem is solved by providing a protrusion 26 on a short lever arm 25.The triangular sliding member 27 is here suitably rounded off, somewhatat its nose or tip, where the protrusion 26 engages. The protrusion 26extends the effective length of lever arm 25, as a result of which agreater force must be exerted on the jaw for overcoming the force of thespring. Moreover, the lateral displacement of sliding member 27 beginswith a certain delay. This special construction of the short lever armserves the purpose of permitting convenient adjustment of the spring tothe conditions of skiing, as a function of the path of travel of thejaw. In addition, the securing head according to the invention, presentsnumerous possibilities, but with the stroke reduction of the springbeing the essential feature. It is further advantageous in the instantsecuring head that when one jaw moves out laterally, thenonparticipating jaw does not become loose since it is continued to beacted upon by the force of the spring but that the latter remains loadedby the spring force. It may be stated by way of a practical example thatthe stroke or movement of the tip of the short lever arms 16 reachesapproximately 9 millimeters when the jaw is swung out to its maximum,whereas the stroke or movement of sliding member 9 amounts only to halfas much, i.e. approximately 4.5 mm. It would be impossible in view ofthe limited space available in a ski binding to provide a spring havingusable tensions which would produce the same characteristics as obtainedwith the use of a stroke reducer, or motion or displacement limitingmember.

The securing head pursuant to the invention can be used as a toe part aswell as a heel part in a safety ski binding, with the toe part, forexample, being raisable by means of a hinge-joint 3, as shown in FIG. Iin order to facilitate easy stepping into the ski binding.

It should be apparent from the foregoing detailed description, that theobjects set forth at the outset to the specification have beensuccessfully achieved.

lclaim:

l. A securing head for a safety ski binding that is capable of use as atoe binding member or a heel binding member and including twolever-shaped jaws cngageable with a ski boot, means mounting each ofsaid jaws for turning movement about an axis extending approximatelyvertical in relation to a ski and spaced transversely thereof, at leastone spring cooperably related with said jaws to urge them to an innerski boot engaging position, each jaw comprising a double arm leverhaving a long lever arm engageable with a ski boot and a short lever armextending inwardly of and substantially perpendicular to said long arm,and said spring acting on said short lever arms, and a motion limitingmember interposed between said spring and said short lever arms so as toreduce the axial movement of the spring in relation to the movement ofthe short lever arms.

2. A securing head as claimed in claim I, in which said motion limitingmember is a sliding member slidablc on the end surface of one of saidshort lever arms and performing a lateral movement when retracted.

3. A securing head as claimed in claim 2, in which said slidable memberis triangular in shape and includes side surfaces cooperable with theend surfaces of said short lever arms and a base surface constituting asupport surface for said spring.

4. A securing head as claimed in claim 2 and further including aheadpiece, each double arm lever comprising an angle lever, each shortlever arm of said double arm levers contacting in normal position saidheadpiece and an adjusting screw supported by said headpiece forcontinuously adjusting the tension of said spring.

5. A securing head as claimed in claim 4, in which said sliding memberand pressure spring surround said adjusting screw, a first spring washerin threaded engagement with said adjusting screw and a second springwasher surrounding said adjusting screw and bearing against said slidingmember with said spring being interposed between said washers.

6. A securing head as claimed in claim I in which one of said shortlever arms has a short marginal protrusion.

7. A securing head as claimed in claim 1, in which said short lever armsare of unequal effective length so that the force pushing the jaws outof their normal position is of unequal magnitude.

8. A securing head as claimed in claim 1, in which the longer of saidshort lever arms is provided on the jaw engageable with the ski boot onthe inside of the foot.

9. A securing head as claimed inclaim 1. in which said motion limitingmember is a slidable member having the shape of a segment of a circle.

10. A securing head for a safety ski binding comprising a base plateadapted to be secured to a ski, a headpiece carried by said baseplateand having a surface extending transversely of the axis of a ski, saidheadpiece further having a bore therethrough extending longitudinally ofa ski, a pair of ski boot engaging jaws. each jaw comprising a doublearm lever having a long lever arm and a short lever arm, means pivotingeach said double arm levers relative to said baseplate for turningmovement about axes extending approximately vertically and alignedtransversely of the ski, located in spaced relation to said surface ofsaid headpiece with said long lever anns constituting ski boot engagingarms and said short lever arms ex tending toward one another and in skiboot engaging position bearing against said surface of said headpiece.an adjusting screw passing through said bore in said headpiece andhaving an externally threaded end portion, a first washer means inthreaded engagement with said externally threaded end portion, a secondwasher means surrounding said adjusting screw and longitudinally movabletherealong. a spring surrounding said adjusting screw and disposedbetween said washer means, and a displacement limiting member looselysurrounding said adjusting screw, slidably related to said second washermeans and including surfaces bearing against said short arms of saiddouble arm levers to hold them against said surface of said headpiece innormal ski binding position of said jaws and to allow lateral shiftingof said member as a long arm of a double arm lever is displacedlaterally outwards due to lateral forces acting on the binding duringskiing.

1. 6A securing head for a safety ski binding that is capable of use as atoe binding member or a heel binding member and including twolever-shaped jaws engageable with a ski boot, means mounting each ofsaid jaws for turning movement about an axis extending approximatelyvertical in relation to a ski and spaced transversely thereof, at leastone spring cooperably related with said jaws to urge them to an innerski boot engaging position, each jaw comprising a double arm leverhaving a long lever arm engageable with a ski boot and a short lever armextending inwardly of and substantially perpendicular to said long arm,and said spring acting on said short lever arms, and a motion limitingmember interposed between said spring and said short lever arms so as toreduce the axial movement of the spring in relation to the movement ofthe short lever arms.
 2. A securing head as claimed in claim 1, in whichsaid motion limiting member is a sliding member slidable on the endsurface of one of said short lever arms and performing a lateralmovement when retracted.
 3. A securing head as claimed in claim 2, inwhich said slidable member is triangular in shape and includes sidesurfaces cooperable with the end surfaces of said short lever arms and abase surface constituting a support surface for said spring.
 4. Asecuring head as claimed in claim 2 and further including a headpiece,each double arm lever comprising an angle lever, each short lever arm ofsaid double arm levers contacting in normal position said headpiece andan adjusting screw supported by said headpiece for continuouslyadjusting the tension of said spring.
 5. A securing head as claimed inclaim 4, in which said sliding member and pressure spring surround saidadjusting screw, a first spring washer in threaded engagement with saidadjusting screw and a second spring washer surrounding said adjustingscrew and bearing against said sliding member with said spring beinginterposed between said washers.
 6. A securing head as claimed in claim1 in which one of said short lever arms has a short marginal protrusion.7. A securing head as claimed in claim 1, in which said short lever armsare of unequal effective length so that the force pushing the jaws outof their normal position is of unequal magnitude.
 8. A securing head asclaimed in claim 1, in which the longer of said short lever arms isprovided on the jaw engageable with the ski boot on the inside of thefoot.
 9. A securing head as claimed in claim 1, in which said motionlimiting member is a slidable member having the shape of a segment of acircle.
 10. A securing head for a safety ski binding comprising a baseplate adapted to be secured to a ski, a headpiece carried by saidbaseplate and having a surface extending transversely of the axis of aski, said headpiece further having a bore therethrough extendinglongitudinally of a ski, a pair of ski boot engaging jaws, each jawcomprising a double arm lever having a long lever arm and a short leverarm, means pivoting each said double arm levers relative to saidbaseplate for turning movement about axes extending approximatelyvertically and aligned transversely of the ski, located in spacedrelation to said surface of said headpiece with said long lever armsconstituting ski boot engaging arms and said short lever arms extendingtoward one another and in ski boot engaging position bearing againstsaid surface of said headpiece, an adjusting screw passing through saidbore in said headpiece and having an externally threaded end portion, afirst washer means in threaded engagement with said externally threadedend portion, a second washer means surrounding said adjusting screw andlongitudinally movable therealong, a spring surrounding said adjustingscrew and disposed between said washer means, and a displacementlimiting member loosely surrounding said adjusting screw, slidablyrelated to said second washer means and including surfaces bearingagainst said short arms of said double arm levers to hOld them againstsaid surface of said headpiece in normal ski binding position of saidjaws and to allow lateral shifting of said member as a long arm of adouble arm lever is displaced laterally outwards due to lateral forcesacting on the binding during skiing.